1. Field of the Invention
The present invention relates to flow indicators and valves for use in liquid carrying conduits, and more particularly, to a device for indicating the presence of a flow of liquid, the rate of that flow, and providing valve means for preventing the reverse flow of the liquid.
2. Description of the Prior Art
The use of flow indicators, flow meters and check valves in liquid carrying conduits is well known in the art and each such device provides a specific function. The flow indicators indicate the presence of a flow of liquid through a given conduit, the flow meters indicate the rate of flow of liquid through the conduit, and the check valves stop the flow of liquid in a given direction.
To Applicant's knowledge, there are no devices which have been developed for performing all three functions, and numerous needs for such a device exist in industries utilizing liquid flow conduits. An example of such a need is in the solar industry wherein a heat transfer liquid transfers heat from the collector to a storage tank by circulating the liquid in a closed fluid conduit through the collector and a heat exchanger in the storage tank.
In such solar systems, it is frequently desirable and/or necessary to make sure that the heat transfer fluid is circulating and that it is circulating at a desirable rate. Also, in some such solar systems, it is desirable to prevent reverse flow of the liquid and it is to achieve the above ends that the present invention was developed.
Accordingly, it is a primary object of the present invention to provide a device for use in liquid flow conduits which indicates the flow of liquid through the conduit, indicates the rate of flow of the liquid through the conduit, and provides a check valve for preventing the reverse flow of liquid through the conduit, if desired.